1. Field of the Invention
The present invention relates to a sheet feeding system and, more particularly, to a sheet feeding system adapted to offset sheets of material for a sheet stacker.
2. Prior Art
Many different feeding devices are known in the sheet feeding art. For example, U.S. Pat. No. 5,639,080 discloses a system for handling purged sheets in the output of a printer which offsets print job sets relative to one another and also offsets purge sheets from regular job sheets with a laterally movable stacking tray. The mechanism associated with driving the laterally movable tray adds both cost and complexity to the sheet stacking device in order to provide offsetting capability. U.S. Pat. No. 5,887,996 discloses an apparatus and method for sheet registration using a single sensor that determines the position and skew of a sheet in a paper path. A pair of independently driven nips forward the sheet to a registration position in skew and at the proper time based on the output from the single sensor. Both U.S. Pat. Nos. 5,639,080 and 5,887,996 are herein incorporated by reference in their entirety. There is a desire to provide a sheet feeding system that provides capability to both deskew and offset sheets of material without the cost and complexity associated with a laterally movable tray being required in a sheet stacker.
In accordance with one embodiment of the present invention, a sheet feeder is provided comprising at least two drives that drive a sheet of material along a paper path and at least two sensors that detect a lateral side of the sheet of material. A controller is connected to the two sensors and at least one of the drives. The controller varies the drive velocity of at least one of the drives to shift the lateral position of the sheet of material in a predetermined direction until one of the sensors detects the lateral side.
In accordance with one method of the present invention, a sheet feeder is provided comprising a drive that drives a sheet of material along a paper path and at least three sensors proximate the drive. Two of the sensors detect a skew of the sheet of material, and at least one of the sensors detects the lateral offset of the sheet of material from the paper path. A controller is connected to the sensors and the drive.
In accordance with another embodiment of the present invention, a method of feeding sheets of material is provided comprising the steps of changing the skew of the sheet of material to a predetermined value and then detecting a lateral side of the sheet of material.